Impact test machine

ABSTRACT

AN IMPACE TEST MACHINE FOR IMPACCTING A TEST MEMBER A PLURALITY OF TIMES WITH AN IMPACT TOOL MOUNTED ON A CARRIAGE FOR VERTICAL MOVEMENT ALONG A PAIR OF GUIDE CHANNEL MEMBERS WITH A VERTICALLY RISING CHAIN FLIGHT ADJACENT THE GUIDE CHANNEL MEMBERS AND A LATCH BAR ENGAGEABLE WITH THE RISING CHAIN FLIGHT TO LIFT THE CARRIAGE TO AN UPPER POSITION AND A PIVOT PLATE ENGAGING THE LATCH BAR AND PIVOTED BY A STOP ON THE TOP OF ONE OF THE GUIDE CHANNELSFOR MOVING THE LATCH TO A RETRACTED POSITION FOR RETENTION BY DETENT MEANS SO THAT THE CARRIAGE AND IMPACT TOOL FALL UNDER THE INFLUENCE OF GRAVITY TO IMPACT AGAINST A TEST MEMBER WITH THE PIVOT PLATE INCLUDING AN INERTIA ARM ACTIVATED BY THE IMPACT WITH THE TEST MEMBER FOR PERMITTING RETURN OF THE LATCH BAR INTO ENGAGEMENT WITH THE RISING CHAIN FLIGHT SO THAT THE CARRIAGE WILL BE LIFTED UPWARDLY TO INITATE REPETITION OF THE CYCLE OF OPERATION. D R A W I N G

March 2, 1971 owNm ETAL 3,566,668

IMPACT TEST MACHINE Filed July 50, 1969 3 Sheets-Sheet 1 L0 INVEN'T R3 James E-Baowuma Dawn: ig-Youuoauooo mum 415M 5m 4 TOBNEV$ March 2, 1971 J BROWNING EIAL I 3,566,668

IMPACT TEST MACHINE 5 Sheets-Sheet 2 Filed July 30, 1969 INVENTORS J'AMls E-Bkowuma# DAVID l-LYouNqaLouo HTTOENEYS I l I I I I I I I I I E March 2, 1971 EBROWNlNG ETAL IMPACT TEST MACHINE 3 Sheets-Sheet 5 Filed July 30, 1969 m N TE. 8 m D 0 VG O "u mmo fl Nm d a 66 E .B S JW E J 7 M- M m m D m r: m

United States Patent 3,566,668 IMPACT TEST MACHINE James E. Browning and David Hull Youngblood, San Antonio, Tex., assignors to Southern Steel Company, San Antonio, Tex.

Filed July 30, 1969, Ser. No. 846,004 Int. Cl. Gllln 3/34 US. Cl. 73-12 5 Claims ABSTRACT OF THE DISCLOSURE An impact test machine for impacting a test member a plurality of times with an impact tool mounted on a carriage for vertical movement along a pair of guide channel members with a vertically rising chain flight adjacent the guide channel members and a latch bar engageable with the rising chain flight to lift the carriage to an upper position and a pivot plate engaging the latch bar and pivoted by a stop on the top of one of the guide channels for moving the latch to a retracted position for retention by detent means so that the carriage and impact tool fall under the influence of gravity to impact against a test member with the pivot plate including an inertia arm activated by the impact with the test member for permitting return of the latch bar into engagement with the rising chain flight so that the carriage will be lifted upwardly to initiate repetition of the cycle of operation.

BACKGROUND OF THE INVENTION This invention is in the field of testing machines and is specifically directed to a structural testing device for testing the impact resisting qualities of various test materials such as rods or bars of the type particularly used in jail and prison cells and equipment. Even more specifically, this invention is directed to an impact test device for subjecting a test member to a large number of blows from an impact tool dropped from a given height to strike the test member.

Numerous prior art devices have been employed in the impact testing of various materials and, while a number of such devices have proven to be fairly satisfactory, a number of deficiencies such as high initial cost, high cost of operation and high cost of maintenance occasioned by the complexity of such devices have remained a problem for those engaged in the impact testing of various materials.

For example, many of the prior known test devices incorporate a gravity drop system in which an impact member is dropped onto the member being tested. However, it is necessary to provide means for lifting the impact tool to a desired height plus means for releasing the tool in order that it may be dropped to strike the test member. Various complicated systems such as cable and pulley arrangements, electro-magnets, screw thread jack means and the like have been employed for lifting the impact tool to a desired height. Moreover, various complicated latch members, switch means, clutch release systems and the like have been employed for releasing the impact tool at the proper position. Unfortunately, none of the prior known devices has proven to be reliable or economical under constant usage. Consequently, the cost of manufacturing, using and maintaining the prior known devices has been excessive.

Specific examples of prior known testing devices over which this invention is an improvement include US. Pat. No. 2,755,658 which employs magnetic means for maintaining and releasing an impact plate and US. Pat. No. 2,890,766 which employs the screw thread system for lifting a drop member to a given height. Other prior known test devices over which this invention is an im- 3,566,668 Patented Mar. 2, 1971 ice provement include US. Pat. No. 1,604,089 in which a complicated toggle arrangement is employed for lifting a test hammer and US. Pat. No. 2,740,286 employing a plurality of pulley members for providing the necessary lift for enabling a gravity drop of a test member.

This invention, on the other hand, provides a uniquely simple, rugged and reliable constantly driven chain means for lifting an impact tool member to a desired height for release by simple and reliable latch to fall by gravity to impact on the test member. Moreover, the latch member is automatically activated to repeat-the cycle upon impact of the tool with the test member.

SUMMARY OF THE INVENTION Therefore, it is the primary object of this invention to provide a new and improved impact test machine.

Obtainment of the object of this invention is enabled through the provision of a test machine incorporating a pair of vertical guide channel members which guide an impact tool bearing carriage mounted for reciprocation thereon. The carriage includes a horizontally reciprocable latch bar which is movable into engagement with a vertically moving electric motor driven chain flight located adjacent one of the guide members. Engagement of the latch bar with the chain flight causes the carriage to be lifted upwardly to a predetermined position adjacent the top of the guide channel members. A pair of test member supporting plates are located adjacent the bottom ends of the guide members so that the impact tool, when dropped, will strike the test member. A stop means is positioned adjacent the upper end of the guide members to be engaged by an actuator plate on the carriage so that the actuator plate is pivoted by the stop means to move the latch bar rearwardly out of engagement with the rising chain flight. The latch bar is retained in its retracted position by detent means so that the carriage and im pact tool consequently fall under the action of gravity to impact against the test member. An inertia arm on the impact tool carriage is pivoted downwardly by the force of the impact of the impact tool with the test member to consequently permit a spring means biassing the latch bar to return the latch bar into engagement with the rising chain flight to initiate repetition of the cycle of operation. The cycle of operation can be repeated literally thousands of times without human intervention until the required number of impact blows have been made or until the test member is broken or destroyed.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of the preferred embodiment of this invention;

FIG. 2 is a side elevational view of the preferred embodiment of this invention;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along lines 44 of FIG. 1;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 1;

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 5;

FIG. 7 is a sectional view taken along lines 77 of FIG. 1; and

FIG. 8 is an enlarged sectional view of the carriage means and a portion of the guide track of the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT Attention is initially invited to FIG. 1 which illustrates the preferred embodiment of this invention which is generally designated 20. Support for the preferred emo bodiment is provided by a support platform 22 formed of four exterior channel members 24 which are best illustrated in FIG. 3. A pair of interior channel members 26 extend in parallel relationship between two of the exterior channel members 24 as shown in FIG. 3 and are, in turn, connected by first and second test member support plates 28 and 30 which are provided with a circular aperture for supporting a test member 32. Channel members 24 and 26 plates 28 and 30 are all welded to a bed plate 33 to provide a strong unitary support for the device. Test member 32 is retained in position on support plates 28 and 30 by a back plate 34 which is also welded to bed plate 33 and a pivotable cover plate 36 attached to the second test member support plate 30 as shown in FIGS. 1 and 3.

Guide means in the form of first and second vertically oriented rigid guide members 38 and 40 respectively extend upwardly above each of the interior channel members 26 and are connected by a top brace member 42 as shown in FIG. 1. Each guide member comprises a channel member 41 of conventional form having a pair of bars 43 of rectangular cross'section welded to its base portion as shown in FIG. 5 so that the space between bars 43 defines a guide slot on each guide member. Additional rigidity is imparted to the lower ends of the guide members by virtue of a centrally apertured plate 44 which is also connected to the interior channel members 26 as shown in FIG. 3.

Power for operation of the preferred embodiment is provided by an electric drive motor 46 through a stepdown transmission 48 which has an output shaft 50 to which an output drive sprocket 52 is keyed. A drive chain 54 connects the output drive sprocket 52 to a power input sprocket 56 keyed to a rotary drive shaft 58 mounted for rotation in bearing brackets 60 adjacent the first guide member 38 as best shown in FIG. 3. A chain drive sprocket 62 is keyed to the other end of the rotary drive shaft 58 as shown in FIG. 3 An idler sprocket 66 is keyed to an idler shaft 68 in rotary bearings 70 on hearing plate 72 which is attached to the upper end of the first guide member 38.

An elevator chain 74 extends between the idler sprocket 66 and chain drive sprocket 62 as best shown in FIG. 1. Electric motor 46 is driven in a direction so that the righthand flight 76 of chain 74 is constantly moving upwardly in an obvious manner.

A carriage generally designated 78 in FIG. 1 is mounted for vertical movement between the guide members 38 and 40 and has an impact tool member 80 extending from its lowermost portions as shown in FIG. 1.

Carriage 78 is formed of a main block member 82 which provides rigidity and ruggedness for the carriage and constitutes the main mass of the carriage for providing substantial momentum for the tool member 80 during operation of the device. Each side of the main block member 82 has a vertically oriented guide rib 84 welded thereto with the ribs 84 being matingly received within the slots between each of the rectangular bars 43 of each of the respective guide means 38 and 40 as best illustrated in FIG. 5. Consequently, the main block member 82 and attachments connected thereto, which are discussed hereinafter, is easily reciprocable along the length of the guide members 38 and 40 but is restrained from lateral movement therefrom. A pair of latch bar retaining plates 86 separated by a pair of spacer guide blocks 88 provide support and guidance for a latch bar 90 mounted for reciprocation within the confines of the opening defined by members 88 and 86. Additionally, the exterior plate 86 is provided with a slot (FIG. 8) through which cylindrical lug 102 extends from latch bar 90 for limiting the extent of reciprocable movement possible for the latch bar.

Latch bar 90 is biassed to the left to an extended position as viewed in FIG. 6 by means of a coil compression spring 104 which is received in an aperture in the right 4 end of the latch bar and supported on a glide rod 106 extending from a vertical separator block 108 located between the plates 86. Plates 86 and the respective separator blocks 88, 108 are connected to the main block member 82 by a plurality of screw members 110 to provide a rigid construction.

It should be noted that the latch bar 90 is movable between two limit positions determined by the relationship between slot 100 and the cylindrical lug 102. These positions consist of a first or extended position illustrated in FIG. 6 in which the end of the latch bar extends outwardly into engagement with the rising flight 76 for the purpose of lifting the latch bar and carriage 78, etc., upwardly along the guide members 38 and 40' and a second, or retracted, position illustrated in FIG. 8 in which there is no engagement between the latch bar and the upward moving flight 76. Consequently, when the latch bar is in the retracted position, the carriage is free to move vertically under the influence of gravity. Latch bar control means for positioning the latch bar includes a pivot plate 114 attached to one end of a pivot shaft 116 which extends horizontally through a bore in the main block member 82. Pivot plate 114 includes a latch bar engaging arm 118 extending a generally downward direction from the pivot shaft 116 and an inertia arm 120 extending outwardly in a horizontal direction from the pivot shaft 116.

Detent means is provided for positioning the pivot plate in a first position in which the latch bar engaging arm permits the latch bar to assume its extended position under the influence of spring 104 as shown in FIG. 1 and a second position shown in FIG. 8 in which the latch bar engaging arm 118 moves the latch bar inwardly to its retracted position as shown in FIG. 8. The aforementioned detent means comprises a spring retainer block 122 extending outwardly from the inertia arm 102 and having a compression spring 124 in an interior bore for biassing a detent sphere 126 toward the outermost latch bar mounting and retaining plate 86 as best shown in FIG. 7. A pair of spherical recesses 128 and 130 in the outer, or left, plate 86 in FIG. 7 serve to respectively position the pivot plate in its first and second positions with FIG. 7 illustrating the pivot plate in the first position in which spherical ball 126 is received in the spherical recess 128. FIG. 8 illustrates the position of the parts when the spherical member 126 is received in the upper spherical recess 130. A pivotable actuator plate 132 is connected to the end of pivot shaft 116 opposite the end to which pivot plate 114 is connected as shown in FIG. 7 and is positioned to engage an adjustable stop means in the form of a screw 134 attached to a bracket adjacent the top of the guide member 38 as best shown in FIG. 1.

A plurality of weight plates are connected to the top of block 182 with the number of weight plates being varied to vary the weight of the carriage and the consequent force with which the tool 80 will strike the test member.

Attention is initially invited to FIG. 1 for a discussion of the operation of the preferred embodiment. It should be assumed that electric motor 46 is rotating in a direction so that flight 76 is moving upwardly as shown in FIG. 1 so as to lift the carriage 78 in a vertical direction by virtue of the fact that the latch bar 90 is in its extended position in engagement with the upward moving flight 76. Carriage 78 will continue to be lifted until the actuator arm 132 engages stop 134 at which time the actuator arm 132 will be pivoted downwardly to cause pivot plate 114 to move in a counter clockwise direction from the position illustrated in FIG. 1 to the position illustrated in FIG. 8. This movement of the pivot plate 114 serves to immediately retract the latch bar 90 to the dashed line position illustrated in FIG. 8 so that the carriage 78 is completely released from engagement with the upwardly moving flight 76 and fails under the influence of gravity. Carriage 78 falls downwardly in the direction of the arrow in FIG. 4 so that tool 80 strikes the test member 32 with substantial force. The impact of the tool on the test member causes inertia arm 120 to immediately pivot downwardly in a clockwise direction as shown in FIG. 8 about the axis of shaft 116 so that shaft 116 is pivoted in the same direction along with arm 118 to permit latch bar 90 to return to the extended position illustrated in FIG. 6 in which the upwardly moving chain flight 76 again begins to move the carriage upwardly for repetition of the cycle of operation. Detent 128 will retain the pivot plate 114 in the FIG. 1 position until the carriage reaches its position adjacent the top of the guide members 38 and 40 at which time actuator plate 132 will again engage the stop 134 to pivot the actuator plate into the FIG. 8 position in which it is retained by the upper spherical recess 130 etc. of the detent means.

It should be understood that the device will continue to operate in the aforementioned manner for any desired period of time without the necessity of constant supervision and maintenance. Operation of the device for a given period of time will result in the impact tool striking the test member a given number of times for the desired test purpose. Additionally, the weight of the carriage can be adjusted by varying the number of plates 140 in order to achieve desired test characteristics. In the impact test machine illustrated, sprocket 62 has been located above test member at such a point that the carriage 78 must rebound after striking the test member before latch 90 will engage the chain flight. If the test member is broken, the carriage is below this point and will not rebound and the testing cycle is automatically stopped.

We claim:

1. An impact test machine for testing the impact resistance of a test member, said test machine comprising vertical guide means, test member supporting means for supporting said test member adjacent the bottom of said vertical guide means, carriage means mounted for reciprocation on said vertical guide means, an impact tool carried by said carriage means, an upward moving chain flight adjacent said guide means, movable latch means comprising a reciprocable latch bar carried by said carriage and movable between an extended position in which it engages said chain flight for causing said carriage to be moved upwardly along said vertical guide means and a retracted position not in engagement with said chain flight, latch control means for moving said latch from engagement with said chain flight to said retracted position as said carriage reaches a position near the top of said guide means so that said carriage falls downwardly along said guide means so that said impact tool strikes said test member including spring means normally biassing said reciprocable latch bar towards said extended position for returning said latch means to said extended position in response to the striking of said test member by said impact member and including a pivot plate attached to a horizontal pivot shaft on said carriage with said pivot plate including a latch bar engaging arm and an inertia arm and detent means on said carriage for positioning said pivot plate in a first position in which said latch bar engaging arm permits said latch bar to move to its extended position and a second position in which said latch bar engaging arm engages said latch bar to retain said latch bar in its retracted position.

2. The invention of claim 1 wherein said guide means comprises first and second vertically oriented guide channel members 3. The invention of claim 2 wherein said latch control means additionally includes stop means mounted adjacent the top of one of said guide channel members and an actuator lever connected to said pivot shaft for engagement with said stop means for pivoting said pivot plate from said first position to said second position as said carriage moves upwardly adjacent said stop means.

4. The invention of claim 1 wherein said test member supporting means is spaced beneath said upwardly moving flight such a distance as to enable said carriage to rebound upwardly upon striking the test member in those cases in which the test member is not broken so that said latch will engage said chain with said latch member not being engageable with said chain in those cases in which the test member breaks upon impact of said impact tool.

5. The invention of claim 4 wherein said guide means comprises first and second vertically oriented guide channel members and said latch control means additionally includes stop means mounted adjacent the top of one of said guide channel members and an actuator lever connected to said pivot shaft for engagement with said stop means for pivoting said pivot plate from said first position to said second position as said carriage moves upwardly adjacent said stop means.

References Cited UNITED STATES PATENTS 2,846,869 8/1958 Tyler et al. 7312 FOREIGN PATENTS 874,218 4/1953 Germany 4234.03

OTHER REFERENCES Automatic Impact Tester Instruments and Automation, vol. 27, June 1954, p. 888.

RICHARD C. QUEISSER, Primary Examiner J. WHALEN, Assistant Examiner U.S. Cl. X.R. 

